Microbial pollution in water and its effect on fish

Abstract

A systematic study of microbial contamination of fish grown in ponds in and around Calcutta was initiated as part of the wetland management project in the city. Ponds were either sewage-fed or conventional (i.e., fed by rain and groundwater). Fish from these ponds are used for human consumption, and therefore a quantitative analysis of their microbial content is necessary. When concentrations of Escherichia coli, Salmonelleae (unidentified species), and Staphylococcus aureus in water and different organs of fish from sewage-fed and conventional ponds were compared, water and fish organs from conventional ponds contained about two orders of magnitude more bacterial cells. We tested for Salmonelleae and S. aureus, in addition to E. coli, because of persistent reports from Calcutta hospitals that most enteric and other infectious diseases in this region are caused by these bacteria. Significant linear correlations were found between concentrations of these bacteria in pond water and their recovery from several tissues of the fish.